Python程式:構建樹並執行插入、刪除和顯示操作
當需要構建二叉樹並執行諸如插入元素、刪除元素和顯示樹的元素等操作時,可以使用定義了方法的類。 定義類的例項,並將其用於訪問元素和執行操作。
以下是相同的演示 -
示例
class Tree_struct:
def __init__(self, data=None, parent=None):
self.key = data
self.children = []
self.parent = parent
def set_root(self, data):
self.key = data
def add_node(self, node):
self.children.append(node)
def search_node(self, key):
if self.key == key:
return self
for child in self.children:
temp = child.search_node(key)
if temp is not None:
return temp
return None
def remove_node(self):
parent = self.parent
index = parent.children.index(self)
parent.children.remove(self)
for child in reversed(self.children):
parent.children.insert(index, child)
child.parent = parent
def bfs(self):
queue = [self]
while queue != []:
popped = queue.pop(0)
for child in popped.children:
queue.append(child)
print(popped.key, end=' ')
my_instance = None
print('Menu (this assumes no duplicate keys)')
print('add <data> at root')
print('add <data> below <data>')
print('remove <data>')
print('display')
print('quit')
while True:
do = input('What would you like to do? ').split()
operation = do[0].strip().lower()
if operation == 'add':
data = int(do[1])
new_node = Tree_struct(data)
suboperation = do[2].strip().lower()
if suboperation == 'at':
my_instance = new_node
elif suboperation == 'below':
position = do[3].strip().lower()
key = int(position)
ref_node = None
if my_instance is not None:
ref_node = my_instance.search_node(key)
if ref_node is None:
print('No such key.')
continue
new_node.parent = ref_node
ref_node.add_node(new_node)
elif operation == 'remove':
data = int(do[1])
to_remove = my_instance.search_node(data)
if my_instance == to_remove:
if my_instance.children == []:
my_instance = None
else:
leaf = my_instance.children[0]
while leaf.children != []:
leaf = leaf.children[0]
leaf.parent.children.remove_node(leaf)
leaf.parent = None
leaf.children = my_instance.children
my_instance = leaf
else:
to_remove.remove_node()
elif operation == 'display':
if my_instance is not None:
print('Breadth First Search traversal is : ', end='')
my_instance.bfs()
print()
else:
print('The tree is empty')
elif operation == 'quit':
break輸出
Menu (this assumes no duplicate keys) add <data> at root add <data> below <data> remove <data> display quit What would you like to do? add 5 at root What would you like to do? add 6 below 5 What would you like to do? add 8 below 6 What would you like to do? remove 8 What would you like to do? display Breadth First Search traversal is : 5 6 What would you like to do? quit
解釋
建立具有所需屬性的“Tree_struct”類。
它有一個“init”函式,用於建立一個空列表。
定義另一個名為“set_root”的方法來指定樹的根。
定義另一個名為“add_node”的方法,該方法有助於將節點新增到樹中。
定義另一個名為“search_node”的方法,該方法有助於搜尋特定元素。
定義一個名為“remove_node”的方法,該方法從樹中刪除元素。
定義另一個名為“bfs”的方法,該方法有助於在樹上執行廣度優先搜尋。
建立一個例項並將其賦值為“None”。
獲取使用者輸入,以確定需要執行的操作。
根據使用者的選擇執行操作。
在控制檯上顯示相關的輸出。
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